1. Field of the Invention
The invention refers to a safety line-connector for electrical connections with two matching connecting parts which fit together, each of which contains contact pieces for connecting to wiring, and one of which contains a switch mechanism through which at least one of its contact pieces is connected with its wiring terminal only when the connecting parts are fitted together.
2. Description of the Prior Art
The most common line-connectors are sockets and plugs of the most various types. Such plug connections assure a good electrical connection of the lines when the plug pins are seated right in the sockets, but are in the simplest models not contact safe. In order to attain sufficient contact safety with such simple outlets, especially for playing children, the well-known safety disc inserts have been developed, which, when inserted in the outlets, permit access to the socket openings only after adjustment of a cover disc held in the closed position by a spring. After somewhat more frequent use, slight damage can already occur in the safety disc inserts, which makes the insertion of a plug, which even normally requires a certain skill, into a laborious task, so that the disc inserts are frequently taken out again.
With plug devices for voltages above 250 V, the outlet is often combined with a switch which must be turned off before the plug can be withdrawn. The providing of switch contacts between sockets and voltage-carrying lines provides a satisfactory degree of contact safety for the outlets, and so it has also already been suggested that a magnetic switch in the outlet be provided, which, for example, is operable by a permanent magnet built into the plug, so that when the plug is inserted into and withdrawn from the outlet, the switch is automatically closed and opened, respectively, and there is no voltage in the socket when the plug is not in it German DE-OS No. 1 515 487).
Not only in trade and industry, but also otherwise in daily life these days, a multiplicity of electrical appliances are used, which are connected by cord and plug to outlets, often also to multiple outlets. Every such "flying" line holds the danger that, for example, when it is stumbled over, an appliance can be pulled from the table, a lamp tipped over, etc., and/or plug and outlet damaged, so that not only costly damages can arise, but it can also result in an accident. The traditional plug devices therefore in no way meet all safety requirements; not even when they are made safe from contact.
It is an object of the invention to create a safety line-connector which is not only safe from contact but also from the aforementioned mechanical influences and the like, and which is in addition simple to operate, cost-saving to produce and can also be produced in small sizes.
The invention's solution to the task consists in the contact pieces of the connecting parts being flush contacts, and each connecting part having a part of a holding-magnet arrangement containing at least one permanent magnet. The holding-magnet arrangement is hereby so calculated that when the connecting parts are brought together, a contact pressure sufficient for a secure contact between the flush contact pieces is maintained, but the connecting parts can be easily separated by an unintentional mechanical influence, so that practically no damage can occur. Because of the switch mechanism contained in the first connecting part, which is connected, for instance, to a source of current, the line-connector is contact-safe. The permanent magnet of the holding-magnet arrangement is functionally contained in a second connecting part connected, for example, to an appliance. The presence of this permanent magnet makes it expedient to use a magnetic switch as switching device, although any other switching device desired can be used, as long as there is assurance that when the connecting parts are separated the hot switch piece of the first connecting part is kept free of voltage by the switch device.
In the further development of the invention, the holding-magnet in the first connecting part, which contains the switch device, is movable from an unoperated position in which the switch device is set to break the connection between the contact piece and its wiring terminal, into an operated position, in which the connection between contact piece and wiring terminal is made and the permanent magnet contained in the second connecting part serves to move the holding-magnet part in the first connecting part. The movable holding-magnet part is in the first connecting part preferably arranged in a space closed off by a plate on the front of the connecting part, so that neither dust nor moisture can penetrate into the connecting part. In the further development of the invention, with a simple line-connector especially suited for low currents, the plate closing off the space with the holding-magnet is itself a contact piece, and the permanent magnet contained in the second connecting part and fitting to this plate carries the opposite contact to this plate-contact piece, whereby when the movable holding-magnet part is in the operated position, the opposite contact is electrically connected through the contact plate, the movable holding-magnet part and the switch device to its wiring terminal. Such line-connectors can be produced in very small sizes, as are common in many cases, especially for the connecting of small appliances.
In a further development of the invention, both parts of the holding-magnet arrangement are cylindrical bodies and each further contact piece of the first and second connecting parts is a ring-segment-contact concentric with the holding magnet part, so that the line connector is polarized.